The underground cavern group is characterized by various structural sections,a complex ventilation network,and multiple sources of pollution.Conducting a study on the transport characteristics of pollutants in the cavern during construction is crucial for enhancing the ventilation scheme and maximizing the efficiency of construction ventilation.In order to address issues such as the significant amount of pollution during different construction stages of a complex underground cavern group,the challenges of integrating ventilation schemes in real-time with construction progress,and the complexities of the air flow field,a large-scale model test was conducted to investigate the transport behavior of pollutants within the cavern.The findings indicate that as the distance of dust migration during ventilation decreases,the peak value of dust mass concentration detected increases.Additionally,a higher initial mass concentration of dust in the tunnel chamber results in a larger peak value of dust mass concentration at the tunnel exit,with the peak value being approximately half of the initial mass concentration.Furthermore,regardless of the initial dust mass concentration in the cave,it takes approximately 60 s for the dust mass concentration to reach its peak.The time required for dust removal is logarithmically correlated with the migration distance,initial mass concentration,and ventilation wind speed.As the dust migration distance and initial mass concentration within the cavern increase,the time needed to reduce the dust mass concentration also increases,albeit with a diminishing rate of increase.Conversely,as the wind speed at the tunnel inlet and wind pipe outlet increases,the time it takes for the dust mass concentration to decrease decreases,resulting in a gradual reduction in the same range of reduction.Taking into account both dust removal efficiency and energy consumption,the following wind speed settings are recommended:a wind speed of 1.5 m/s at the outlet of the duct,a wind speed of 3.0 m/s at the inlet of the tunnel,a wind speed of 0.5 m/s at the inlet of the tunnel,and a wind speed of 2.5 m/s at the outlet of the duct.The combination of these two wind speeds facilitates effective dust discharge.To target the areas with high dust mass concentration within the cavern,the position of the air pipe is optimized to align with the cavern wall.Furthermore,the number of vortex zones on the wall is minimized to reduce the dust mass concentration.
关键词
安全卫生工程技术/地下洞室群/污染物运移/模型试验/通风风速
Key words
safety and hygiene engineering technology/underground cavern groups/transport of pollutant/model test/ventilation speed
维普
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